The present invention relates to a coupling mechanism which is suitable to interconnect a plurality of display units successively, the display unit each having a number of display elements. Additionally, the present invention relates to an image display device which is produced by connecting the above display units with each other at least in a vertical direction of the display units to display screen images.
As often come across, image display devices, each of which includes a number of display elements such as light emitting diode (LED) forming a display screen image, are installed in indoor/outdoor stadiums, various event sites, a billboard of a building facing a busy downtown street, etc.
These image display devices may be located in stadiums or building structures on a permanent basis. Alternatively, they may be assembled on a case-by-case basis at various event sites around the country or mounted on respective beds of heavy vehicles.
This kind of image display device is capable of full-color displaying with RGB (red-green-blue) lighting control, thereby promo-displaying, guidance-displaying for customers or displaying of television images for audiences. Generally, the image display device includes a plurality of display units that are connected with each other vertically and horizontally through coupling tools or connecting tools (Japanese Patent Application Laid-open No. 2003-348493).
FIG. 1 is a perspective view of the substantial part of a conventional image display device where the above display units are connected with each other. FIG. 2 is a perspective view of the substantial part of the image display device where the display units 1, 1 are connected with each other in a vertical direction, also viewed from the rear side.
In FIGS. 1 and 2, each of the display units 1 includes a plurality of display panels 11 [e.g. 12 (=3×4) panels in FIG. 1] and a box-shaped casing 12 equipped, on its front side, with the display panels 11. Each display panel 11 has a number of display elements 11a arranged in a matrix manner. Generally, the weight of one display unit 1 amounts to 30 kg in case of the display elements of LED.
In the casing 12, a joint pin 2 is arranged at the center of the top surface of the casing 12 to connect the display unit 1 with a not-shown mating display unit to be mounted thereon. On both sides of the joint pin 2, the casing 12 further includes two guide pins 121, 121 for guiding the connection between two casings 12 in vertical arrangement.
The joint pin 2 is equipped, at its upper part, with a penetrating engagement rod 2a, providing a T-shaped configuration. As shown in FIG. 2, the joint pin 2 is connected to an engagement part 3 attached to a lower part of the mating display unit 1 to be mounted on the display unit 1 having the joint pin 2.
In this way, the above-mentioned joint pin 2 and the engagement part 3 do constitute a conventional coupling tool (or coupling mechanism) used in connecting the display units 1, 1 with each other in the vertical direction to form the above image display device.
FIG. 3 is an enlarged perspective view of the substantial part of a coupling mechanism having the above conventional coupling tool. As mentioned above, the upper display unit (not shown) is provided, at its lower end, with the engagement part 3 having a pair of hooks 31. While, the lower display unit (not shown) is provided, at its upper end, with the joint pin 2 having the engagement rod 2a. In the course of connecting the lower display unit with the upper display unit, when tile hooks 31 of the engagement part 3 of the upper display unit trap the engagement rod 2a of the joint pin 2 of the lower display unit, a handle 32 linked to the hooks 31 is rotated upwardly. Then, the rotation of the handle 32 allows a stopper 33 to locks up a coupling between the upper and lower display units.
In the above-constructed coupling mechanism, the upper display unit can be disconnected from the lower display unit by first pushing down the stopper 33 and subsequently manipulating the handle 32.
Note, as shown in FIGS. 1 and 2, each display unit 1 is provided, on both side surfaces thereof, with two pairs of connecting tools 4 (41), 4 (42) forming hook joints. These connecting tools 4 are provided to connect the horizontally-adjoining display units 1, 1 with each other.
FIG. 4A is a front view of the substantial part of the conventional image display device. FIG. 4B is a plan view of the substantial part of the conventional image display device. The illustrated image display device is completed by horizontally and vertically coupling a plurality of display units 1, 1 to each other with the use of the above-mentioned coupling mechanisms and the above connecting tools 4, providing a large display screen.
As another example of the conventional art, there is also known a hose coupling allowing flexible tubes (e.g. hoses) to be connected/disconnected to and from each other through an operator's one-touch operation (see Japanese Patent Application Laid-open No. 2001-254885).
The above-mentioned conventional coupling mechanism is constructed so as to allow the display units to be connected/disconnected to and from each other by an operator's manipulation of the handle. In order to accomplish the operator's proper manipulation of the handle, however, the above hooks 31 and the other coupling components have to be processed with high accuracy. Additionally, due to the structure using the T-shaped joint pin 2, the coupling mechanism has a complex structure formed by a number of components.